Preparation of an acrylonitrile-methyl acrylate-methyl vinylpyridine ternary polymer



United States Patent PREPARATION OF AN A'CRYLONITRILE-METHYL ACRYLATE METHYL VINYLPYRIDINE TER- NARY POLYMER John A. Price, Stamford, and John J. Padbury, Springdale, Conn., 'assignors to American Cyanamid Company, New York, N.Y., a corporation of Maine N0 Drawing. Application July 3, 1953 Serial No. 366,067

1 Claim. (Cl. 260-455) This invention relates to the production of new synthetic materials having valuable and characteristic properties, and more particularly is concerned with polymerized acrylonitrile compositions and specifically copolymers of acrylonitrile. The scope of the invention includes the preparation of compositions comprising a ternary polymer containing in the polymer molecule an average of, by weight, from 2 to 10% of methyl acrylate units, from 1.5 to 15% of units of methyl vinylpyridine represented by the formula and the remainder acrylonitrile units.

The suggestion was made prior to our invention that various acrylonitrile copolymer compositions could be prepared by polymerizing acrylonitrile either, alone or admixed with various other monomers which are copolymerizable therewith, including such monomers as methyl methacrylate and other esters of methacrylic acid, esters of acrylic and alpha-chloroacrylic acids, vinyl chloride, acrylamide, vinyl acetate and 2-vinylpyridine. For example, in Arnold Patent No. 2,456,360 there is disclosed and claimed a process of polymerizing an acrylonitn'le composition wherein the polymerizable portion is substantially entirely monoethylenically unsaturated and is at least 90% acrylonitrile, the remainder being such monomers as have just been mentioned, and the process itself involving carrying out the polymerization reaction in the presence of from 0.01 to 2%, by weight of the polymerizable components, of dithioglycidol. Also, Arnold Patent No. 2,491,471 discloses and claims copolymers containing from 2 to 10% recurring vinylpyridine units, the remainder of the copolymer consisting of acrylonitrile units.

While the copolymers of the prior art described above have had many useful applications, for instance in the production of synthetic fibers, there have been many instances where such copolymers did not have the neces sary solubility, dyeability and spinnability to meet the particular requirements encountered in a particular application or methed of producing the shaped article therefrom.

The present invention has, as one of its main objects, the production of new acrylonitrile copolymer compositions which are more readily capable of being both fabricated (e.g., in fiber or other form) and dyed, especially with acid dyes, than homopolymeric acrylonitrile and copolymers of acrylonitrile such as those suggested in the prior art.

Another object of the invention is to prepare such copolymers which can be converted readily into fabricated articles, e.g., textile materials including oriented fibers of fiber-forming polymeric material comprising a ternary polymer of the kind described above; and

2 the fabricated article then dyed, advantageously with an acid dye.

Still another object of the invention is to prepare readily dyeable copolymers which can be dissolved in suitable solvents, e.g., dimethyl formamide, and the re sulting spinning solution then either wetor dry-spun to yield an oriented fiber that subsequently can be dyed, if desired, with an acid or other dyestufi.

Another object of the invention is to produce dyeable copolymers that can be wetor dry-spun and the resulting fiber oriented to a high degree, as by stretching, to form an oriented fiber which is readily receptive to acid and other dyestuffs, without detracting in any Way from the other useful properties of the material.

Other objects of the invention will be apparent to those skilled in the art from the description and examples which follow.

These objects are accomplished, in general, by preparing a copolymer, more particularly a ternary polymer, of acrylonitrile, methyl acrylate, and a methyl vinylpyridine, using proportions of each of these ingredients so that the final ternary polymer contains in the polymer molecule an average of, by weight, from 2 to 15% of methyl acrylate units, advantageously from 3 to 10% of such units; from 1.5 to 15% of units of a methyl vinylpyridine represented by the formula given in the first paragraph of this specification, advantageously from 2 to 10% of such units (and still more particularly from 2 to 10% of units of methyl vinylpyridine consisting mainly of Z-methyl-S-vinylpyridine units); and the remainder acrylonitrile units.

Various methods can be employed to prepare the ternary polymers of a methyl vinylpyridine (including acid-addition salts thereof), methyl acrylate and acrylonitrile with which this invention is concerned. Heat, light, or both heat and light, with or Without a polymerization catalyst, can be used. A polymerization catalyst preferably is employed in order to shorten the period of time required for polymerization of the mixture of monomers. Any of the polymerizationcatalysts which are suitable for use in polymerizing compounds containing an ethylenically unsaturated grouping, specifically a vinyl grouping, can be employed. Among such catalysts are the various organic peroxy catalysts, illustrative examples of which latter are: the dialltyl peroxides, e.g., diethyl peroxide, dipropyl peroxide, dibutyl. peroxide, dilauryl peroxide, dioleyl peroxide, distearyl peroxide, di- (tert.-butyl) peroxide and di-(tert.-amyl) peroxide, such peroxides often being designated as ethyl, propyl, butyl, lauryl, oleyl, stearyl, tert.-butyl and tert.-amyl peroxides; the alkyl hydrogen peroxides, e.g., tert.-butyl hydrogen peroxide (tert.-butyl hydroperoxide), tert.-amyl hydrogen peroxide (tert.-amyl hydroperoxide), etc.; symmetrical diacyl peroxides, for instance peroxides which commonly are known under such names as acetyl peroxide, propionyl peroxide, lauroyl peroxide, stearoyl peroxide, malonyl peroxide, succinyl peroxide, phthaloyl peroxide, benzoyl peroxide, etc.; fatty oil acid peroxides, e.g., coconut oil acid peroxides, etc.; unsymmetrical or mixed diacyl peroxides, e.g., acetyl benzoyl peroxide, propionyl benzoyl peroxide, etc.; terpene oxides, e.g., ascaridole, etc.; and salts of inorganic per-compounds, examples of which are given hereinafter. Other so-called free radical types of catalysts, e.g., a,a'-azodiisobutyronitrile, also can be used to accelerate polymerization. The various known redox (reduction-oxidation) catalyst systems also can be employed, and are especially adapted for use when the mixed monomers are copolymerized in an aqueous: medium. Such water-soluble catalyst systems generally comprise a water-soluble catalyst or catalysts and a water-soluble activator. Illustrative examples of water-soluble catalysts are water-soluble, oxygen-yielding peroxy compounds, e.g., the water-soluble peroxides, peracids and persalts, including hydrogen peroxide, organic peroxide, e.g., diacetyl peroxide, urea peroxide, etc., peracetic acid, the various water-soluble perchlorates, persulfates, percarbonates, perborates, perphosphates, etc., e.g., the ammonium and alkali-metal (sodium, potassium, lithium, etc.) salts of percarbonic, peracetic, perboric, perphosphoric, persulfuric, perchloric, etc., acids; and water-soluble ferric salts capable of yielding ferric ions, including the various ferric alums, e.g., ferric ammonium sulfate (ferric ammonium alum), ferric sodium sulfate, ferric potassium sulfate, etc. Other examples of water-soluble additives comprising a water-soluble catalyst that may be used in producing the copolymers of the present invention are given in, for instance, US. Patents 2,289,540, 2,380,474, 5, 6, 7, 2,380,617, 8, 2,380,710, 2,383,425, 2,384,544, 2,384,571, 2,384,574, 2,388,373 and 2,395,017.

Illustrative examples of water-soluble activators (watersoluble polymerization adjuvants) of the catalyst are oxygen-containing sulfur compounds which are capable of undergoing oxidation, for instance sulfur dioxide, the alkali-metal (e.g., sodium, potassium, etc.) bisulfites, hydrosulfites, thiosulfates, sulfurous acid (or compounds which engender sulfurous acid, e.g., alkali-metal sulfites, ethyl and other alkyl sulfites, etc.), various organic sulfinic acids, e.g., p-toluene sulfinic acid, formamidine sulfinic acid, etc; If alkali-metal sulfites, e.g., sodium sulfite, or similar compounds which engender sulfurous acid are used, the aqueous solution also should contain a strong acid, e.g., sulfuric acid, etc., in an amount which is at least chemically equivalent to the amount of such a compound engendering sulfurous acid that is employed.

If desired, the mixture of monomers can be polymerized in emulsion or in solution state to yield a copolymer. Good results are obtained by effecting copolymerization while the monomers are dissolved in a suitable solvent, preferably water or a liquid solvent comprising mainly water. Suitable inert organic solvents also can be used if desired, e.g., benzene, toluene, xylene, etc. Preferably the copolymerization reaction is carried out in a liquid medium in which the monomeric mixture is soluble but the copolymer is insoluble, e.g., water.

The polymerization also can be effected by conventional bulk polymerization technique, in the presence or absence of a solvent capable of dissolving the monomeric mixture and in which the latter preferably is inert; or by conventional beadpolymerization methods. The polymerization of the mixture of monomers can be effected by a continuous process as well as by a batch operation.

The concentration of the catalyst is relatively small, e.g.,-from, by weight, about 1 part of catalyst per 1000 parts of the monomeric mixture to about 4 or 5 parts of catalyst per 100 parts of the mixture of monomers. The amount of polymerization adjuvant or activator used likewise may be varied considerably, but generally is within the range of from about 0.1 to 1 molar proportion based on the catalyst used or an amount which is chemically equivalent to the amount of catalyst employed. The use of'higher ratios of activator with respect to the catalyst is not precluded, e.g., 2 or 3 or more moles of activator per mole of catalyst, or correspondingly larger proportions on a chemical equivalent basis, but no particular advantages ordinarily accrue therefrom.

The polymerization (copolymerization) reaction may be effected, if desired, while the aqueous medium is maintained under an atmosphere of an inert gas, for example nitrogen, helium, carbon dioxide, etc.; or, it may be (but preferably is not) carried out under an atmosphere of air.

The temperature at which the monomers are copolymerized can be varied over a wide range, up to and including or slightly above the boiling point (at atmospheric pressure) of the monomeric mixture. In most cases, the

4 v i polymerization temperature will be within the range of about 20 or 30 0., preferably at least 35 or 40 C., up to the boiling temperature of the mixture of monomers, depending, for example, upon the particular catalyst, if any, used, the rapidity of polymerization wanted and other influencing factors. The use of poly: merization temperatures substantially above the boiling point of the mixture of monomers is not precluded, but generally is less desirable because the polymerization reaction then must either be carried out in a closed re-. action vessel under pressure, or, for economical reasons, with a reflux condenser or other means provided 'forthe recovery and re-use of the volatilized monomer or monomers if the reaction is carried out at the boiling temperature of the mass under atmospheric pressure.

If desired, the monomers may be copolymerized in the presence of a plasticizer for the copolymer. Other copolymerization methods, however, also may be employed, e.g., methods such as those described in US. Patents 2,140,048, 2,160,054, 2,194,354, 2,333,635, 2,436,926, and British Patent 586,881 with reference to'the production of other polymerization products. The 'acrylonitrile copolymers, specifically acrylonitrile ternary polymers, of this invention, can be producedin various molecular weights, depending, for instance, upon the particular polymerization conditions employed, but ordinarily are within the range of about 15,000 to about 300,000 or higher as calculated from viscosity measurements using the Staudinger equation (reference: U.S. Patent No. 2,404,713). Homogeneous copolymers having an average molecular weight of between about 60,000 and 90,000 and which contain at least preferably from or to 96.5%, of acrylonitrile (combined acrylonitrile) in the molecule, and especially suitablefor use in making dyeable, oriented fibers by wetor dry-spin ning methods.

If the copolymerization reaction is carried out while the mixed monomers are dissolved or dispersed .in .a liquid medium, e.g., in solution in Water, the resulting-cm polymer then is separated from the said medium by any suitable means, e.g., by filtration, centrifuging, solvent extraction, etc.

Instead of methyl vinylpyridine consisting mainly (more than 50% and more particularly about 75 to 85%) of 2-methyl-5-vinylpyridine (3-vinyl-6-methylpyridine) used in the following examples, one can use 2- methyl-S-vinylpyridine which is composed substantially completely of this single isomer; or one can employ other isomers ofmethyl vinylpyridine including:

2-methyl-3-vinylpyridine (5vinyh6-methylpyridine) 3-vinyl-4-methylpyridine (4-methyl-S-Vinylpyridine) 3-vinyl-5-methylpyridine (3-methyl-5vinylpyridine) 2-vinyl-3-methylpyridine 2-vinyl-4-methylpyridine 2 vinyl-5-methylpyridine 2-vinyl-6-methylpyridine 2-methyl-4vinylpyridine 3 -methyl-4-vinylpyridine as Well as mixtures of any or all of the foregoing isomers of methyl vinylpyridine (including 2-methyl 5- vinylpyridine) in any proportions.

In order that those skilled in the art may better understand how the the present invention can be carried into etfect,'the following examples are given by Way of illustration' and not by way of limitation. All parts and percentages are by weight.

Example 1 This example illustrates the preparation of a ternary polymer containing in the polymer molecule an average of, .by weight, about 4.5% of methyl acrylate units, about 2.5% units of methyl vinylpyridine consisting mainly of 2-methyl-5 -vinylpyridine units, and the remainder acrylonitrile units.

The copolymerization is effected. continuously, using apparatus which includes a reaction vessel that is provided with a side arm that serves as an overflow tube and is located about two-thirds of the Way up the side of the reaction vessel. Agitation is effected by means of apropeller (driven by a high-speed induction motor), and a water bath is used for cooling. The solutions of monomeric material and of catalyst, hereafter described, are fed into the reactor using constant-overflow feeddevices including synchronous motors geared to 0.01 and 0.033 rpm. and which are fitted with brass sprocket gears and ladder chains by which they lower weighted plungers into cylinders. The overflowing liquid is forced under low nitrogen pressure into the reactor.

The-reactor is charged with a previously prepared 17% aqueous slurry of the ternary polymer to be produced, and the followingsolutions are then fed in at such a rate that the stated quantities are delivered each hour:

Feed 1: Parts Acrylonitrile (96.9%) 134.3 Methyl acrylate 7.0 tert.-Dodecyl mercaptan 0.3

Feed 2:

Sodium chlorate 1.20 Sodium sulfite 3.82 Demineralized water 346.00

Feed 3: 4

Methyl vinylpyridine consisting mainly of 2- methyl-S-vinylpyridine 3.5 Sulfuric acid 3.6 Demineralized water 342.0

The initial slurry and feeds are purgedwith nitrogen for 30 minutes. The solutions are then fed to the reactor at the aforementioned rates. The. temperature of the slurry is maintained at 45 C. The copolymerization reaction is stopped after. 6 /2 hours, and the pH of the slurry at the end of this reaction period is 2.1.

The ternary polymer is isolated from the reactor slurry by collection on a Biichner funnel, washed with 2000 parts of demineralized water, and dried in an oven at 70 C. for about 16 hours. One hundred and fiftyeight (158) parts of a dry, W to ternary polymer of acrylonitrile, methyl acrylate and methyl vinylpyridine (mainly Z-methyl-S-vinylpyridine) is obtained.

Analysis of this ternary polymer, which is soluble in dimethyl formamide, shows that it contains 4.5% of units derived from methyl acrylate, about 2.5% of units derived from methyl vinylpyridine (mainly 2-methyl-5- vinylpyridine), and the remainder units derived from acrylonitrile.

Instead of charging an aqueous slurry containing about 17% of the previously prepared ternary polymer to the reactor, one can use a slurry containing any other suitable concentration of the ternary polymer (e.g., from 5 or to 35 or 40% by weightof the slurry). Or, if desired, one can use an aqueous .slurry containing a previously prepared homopolymer of acrylonitrile thereby to obtain a blend of the homopolymer and of the ternary polymer with which this invention is concerned, the concentration of the homopolymer in the blend decreasing as the continuous polymerization proceeds. A slurry of other previously prepared copolymers of acrylonitrile similarly can be used instead of slurries of homopolymeric acrylonitrile or of the ternary polymers of this invention. The polymerization reaction advantageously is carried out at a pH not higher than 6, e.g., from 2.5 to 5.9, and preferably from 3.5 or 4 to 5.9.

The foregoing polymerization technique has numerous advantages over the prior-art practices, including the advantages of providing higher overall yields of the ternary polymer; better control of the reaction; the more ready production of acrylonitrile-methyl acrylate-methyl vinylpyn'dine ternary polymers having a specific, predetermined average molecular weight (this latter being pan ticularly important when the ternary polymers are to be formed or fabricated into fibers); the obtainment of a more homogeneous polymeric product (that is, one which contains minimum amounts of polymer having a molecular weight outside the lower and higher limits of molecular weight wanted in the product); as well as others. This polymerization method for producing the ternary polymers of this invention is, to the best of our knowledge and belief, new and novel.

Example 2 This example illustrates the polymer containing in the polymer molecule an average of, by weight, about 4.1% of methyl acrylate units, about 5% of units of methyl vinylpyridine consisting mainly of Z-methyI-S-vinylpyridine uni-ts, and the remainder acrylonitrile units.

The same apparatus and general procedure are employed as in Example 1. The reactor is charged with an aqueous slurry composed of 420 parts of homopolymeric acrylonitrile and 1180 parts of demineralized Water having dissolved therein 2.67 parts of sulfuric acid. The system is purged with nitrogen as in Example 1. The following solutions are then fed in at such a rate that the stated quantities are delivered each hour:

preparation of a ternary Demineralized water 342.00

The temperature of the slurry is maintained! at 45 C., and the copolymerization reaction is stopped at the end of 5 hours. The ternary polymer is isolated from the reactor slurry by collection on a Biichner funnel, washed with demineralized Water, and dried in an oven at 70 C. for about 16 hours. A dry, white, dimethyl formamidesoluble ternary polymer is obtained. Analysis of a sample shows that it contains 4.1 of units derived from methyl acrylate, about 5% of units derived from methyl vinylpyridine (mainly Z-methyl-S-vinylpyridine), and the remainder units derived from acrylonitrile.

Example 3 Example 2 is a repeated substituting an equivalent amount (molar basis) of 2-vinylpyridine for the methyl vinylpyridine (mainly 2-methy -5-vinylpyridine) of that example. The resulting ternary polymer of acrylonitrile methyl acrylate and 2-vinylpyridine is employed in making comparative tests described in examples which follow.

Example 4 Samples of homopolymeric acrylonitrile and of the ternary polymers of Examples 1, 2 and 3 are subjected to the following dye test:

A sample (10 parts) of the dry homopolymer or ternary polymer is added to a dye bath consisting of 500 parts of an aqueous solution containing 0.2 part of concentrated sulfuric acid, 1 part of sodium sulfate and 0.2

part of Calcocid Alizarine Blue SAPG (Color Index No.

1054). The dye bath is boiled for 30 minutes, after which the polymerization product is filtered off and washed with hot water until the water is free of dye. The homopolymeric acrylonitrile fails to absorb any dye.

The ternary polymers of Examples 1 and 3 are dyed to about the same intensity of blue, which shows conclusivelythat 2-vinylpyridine and a methyl vinylpyr dinq other in this relationship, that is, in forming a ternarypolymer thereof with particular proportions of acrylonitrile and methyl acrylate. This non-equivalency is readily apparent when it is considered that it is necessary to introduce into the ternary polymer only about one-half as much methyl vinylpyridine as 2-vinylpyridine in order to produce a polymer which can be dyed to substantially the same'depth of color. This is a difference of substance and not merely of degree, in no way could have been predicted, and is a matter of tremendous practical and economic importance as will be readily apparent to those skilled in the art. Furthermore, these results are obtained without detrimentally atfecting the other useful properties, particularly fiber-forming characteristics, of the ternary polymers of this invention; and this likewise in no way could have been predicted from the known properties of the respective monomers or from the properties of the prior-art polymerization products prepared from the respective monomers.

The ternary polymer of Example 2 is dyed to a much greater depth of blue than the ternary polymers of Ex amplcs 1 and 3. The color comparisons between the ternary polymers of Examples 2 and 3 again show the non-equivalency of an unsubstituted vinylpyridine, specifically 2-vinylpyridine, and a vinylpyridine having a nuclearly-substituted methyl group, when the respective monomers are employed in the particular relationship with which this invention is concerned, that is, in making ternary polymers thereof with particular proportions of acrylonitrile and methyl acrylate.

Example 5 Twenty (20) parts of the ternary polymer of Example 1 is slurried by rapid stirring at room temperature in 80 parts of dimethyl formamide. While protected by a blanket ofcarbon dioxide the temperature of the mixture is raised to 80 C. with slow stirring until all of the copolymer has dissolved to form a clear, viscous solution.

After deaeration and filtration the warm solution is extruded downwardly through a spinneret having 40 holes, each 70 microns in diameter, into a spinning cell, the inner wall of which is maintained at a temperature of approximately 425 C. by means of a fluid heating medium'which circulates around the outer wall of the cell. A current of preheated gas at 125 C. is introduced at the bottom of the cell and passes upwardly countercurrent to the filaments which pass downwardly from the spinneret. By this means the major proportion of the dimethyl formamide is evaporated from the filaments by the time the filaments have reached the bottom of the cell.

From the bottom of the cell the group of filaments or thread is led through water to remove the last of the dimethyl formamide solvent, after which it is continuously. dried by passing it over a pair of heated drying rolls. The dry multifilament thread is then thermoplastically stretched by conducting it through a slot which is maintained at400 C. and thence to stretch rolls. Stretch is applied to the thread by having the surface speed of the rolls on the delivery end of the heated slot 9 times that of the surface speed of the rolls which feed the thread to the slot. The filaments are oriented along thefiber axis by this stretching operation.

The thermoplastically stretched thread is more lustrous than that of the unstretched thread. To remove residual strains or shrinkage, the thread is conducted through a second, heated slot at 400 C. and thence to a pair of rolls, the surface speed of which is adjusted to permit about 15% shrinkage of the thread in the slot. After this thermoplastictreatment the thread is collected on a ring-twister bobbin,

The finished thread is tested for its dyeability, in comparison with threads similarly prepared from homopolymeric acrylonitrile and from the ternary olymers'of Examples 2; and 3, following essentially the same dyetest method described under Example 4.

The fibers or threads made from the ternary polymers of Examples 1 and 3 are dyed to about the same intensity of blue, even through the former contains only half as much methyl vinylpyridine units as the latter contains 2- vinylpyridine units; those made from the ternary polymer of Example 2 are more deeply dyed than those just described; while those made from homopolymeric acrylonitrile are substantially undyedl The spinning characteristics of the ternary polymer of Example 1 are much better than those of the polymer of Example 3, as evidenced, for instance, by the better physical and other properties of the product, less breakages during spinning, and higher stretchability that can be applied, thereby providing more highly oriented fibers. These are advantages of great practical significance, as will be well understood by those skilled in the art.

The ternary polymers of this invention and shaped; articles produced therefrom, e.g., monoand multifilaments, are particularly amenable to dyeing by the process described and claimed in the copending application of Jerry M. Mecco, Serial No. 248,667, filed September 27,. 1951, and wherein are given examples of many classes and species of acid and other dyestuffs with which our new polymers can be readily dyed to deep shades. Dyestuffs disclosed in said Mecco application, and employed. in the processes therein disclosed and claimed, are useful for dyeing our ternary polymers and structures fabricated therefrom.

Although the copolymers produced in accordance with the method of this invention are particularly useful in. the formation of fibers or filaments having improved prop-. erties over that provided by homopolymeric acrylonitrile and the previously known copolymers of acrylonitrile, they also have numerous other applications in the plastics and coating arts. For instance, with or without a filler or other additive, they may be used as molding compositions (or as components of molding compositions) from which molded articles are produced by molding the compositions under heat and pressure, e.g., temperatures of the order of C. or C. to 200 C. and under pressures up to 10,000 pounds or more per square inch. Among the fillers that can be employed in the production of molding compositions are alpha-cellulose pulp, asbestos fibers, cotton flock, chopped cloth cuttings, glass fibers, wood flour, antimony oxide, titanium dioxide, sand, clay, mica dust, diatomaceous earth, etc.

The polymerizable compositions can be used in the production of castings of any desired shape or size; as adhesives; in the treatment of paper or paper stock; in coating compositions; and for various other purposes. The ternaiy polymer can be formed in situ after application of the monomeric mixture to the base material to be coated, impregnated or otherwise treated.

The undyed or dyed shaped articles, more particularly fibers or threads, produced from the ternary polymers of this invention can be fabricated into clothing, blankets, and a wide variety of other textile materials in accordance with conventional practice.

We claim:

The method of preparing a diniethylform amidecoluble ternary polymer containing in the polymer molecule an average of, by weight, about 4.1% of methyl acrylate units, about 5% of units of methyl vinylpyridine consisting mainly of 2-methyl-S-vinylpyridine units, and the remainder acrylonitrile units, said ternary polymer being dyeable to a much greater depth of blue with Calcocid Alizarine Blue SAPG as compared with a similarly prepared ternary polymer wherein there has been substituted an equivalent amount, on a molar basis, of'2 vinylpyridine for'methyl vinylpyridine consistingmainlyof 2-methyl-5-vinylpyridine, said method comprising continuouslyfeeding into an agitated polymerization zone,

asbnoae for continuous conjoint polymerization of the monomer components, the following solutions at such a rate that the hereinafter-stated quantities are delivered each hour:

Feed 1: Parts Acrylonitrile (96.9%) 134.3 Methyl acrylate 7.0 tert.-Dodecyl menoaptan 0.3

Feed 2:

Sodium chlorate 1.20 Sodium sulfite 3.82 Demineralized water 346.00

Feed 3:

Methyl vinylpyridine consisting mainly of Z-methyl-S-vinyl-pyridine 7.13

Sulfuric acid 4.11

Demineralized water 342.00

and said agitated polymerization zone initially containing an aqueous slurry composed of 1) a previously prepared acrylonitrile polymer and (2) demineralized water having dissolved therein 2.67 parts of sulfuric acid, and the ingredients of (1) and (2) being present in the said slurry in a ratio of 420 parts of the former to 1180 parts of the latter, the concentration of the aforesaid previously prepared acrylonitrile polymer in the slurry decreasing as the continuous conjoint polymerization proceeds; maintaining the temperature of the slurry in the polymerization zone at 45 C.; and collecting the aforesaid dimethylformarnide-soluble ternary polymer that is formed.

References Cited in the file of this patent UNITED STATES PATENTS 2,613,194 Craig Oct. 7, 1952 2,654,721 Lytton Oct. 6, 1953 2,657,191 Coover Oct. 27, 1953 2,777,832 Mallison Jan. 15, 1957 FOREIGN PATENTS 500,644 Belgium July 16, 1951 680,359 Great Britain Oct. 1, 1952 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Noo 2,89l,@35 June 16, 1959 John Ao Price et al It is hereby certified that error appears in the printed specification .of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1 line 33,, after the Word "either" strike out the comma; line 59, for "methed" reed method ==5 column 4, line 34,, for "and" read me are column 6, line 53, for "is a repea'lzed read is repeated column 8, line 6, for "through" read though e Signed and sealed this 10th day of November 1959,

Attest:

KARL H0 AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents 

